In manufacturing of an electronic device such as, for example, a semiconductor device, a plasma processing may be performed on a processing target object as a kind of processing in some cases. In the plasma processing, a gas is supplied into a processing container, so that plasma of the gas is generated. When the processing target object is exposed to the plasma, a processing such as, for example, film formation or etching, is performed on the processing target object. As a kind of a plasma processing apparatus for performing such a plasma processing, a capacitively-coupled parallel-flat plate plasma processing apparatus is known.
The parallel-flat plate plasma processing apparatus includes a processing container, a mounting stage, and a shower head. The mounting stage is provided within the processing container, and constitutes a lower electrode. The shower head is a structure for supplying a gas into the processing container, and constitutes an upper electrode. In the plasma processing apparatus, when the gas is supplied into the processing container, a high frequency power is supplied to the upper electrode or the lower electrode. Accordingly, plasma of the gas is generated within the processing container.
Meanwhile, in the plasma processing, the in-plane uniformity in the processing of the processing target object becomes an important factor. As for one method of improving the in-plane uniformity of the plasma processing, there has been suggested a technology of supplying gases having different gas species and/or different flow rates to a central region and a peripheral region of the processing target object, respectively. Such a technology is disclosed in Patent Document 1.
In the technology disclosed in Patent Document 1, an internal space of the shower head is divided into two gas diffusion chambers. A processing gas is supplied to each of the two gas diffusion chambers from a source of the processing gas through a first branch pipe and a second branch pipe. Also, an additional gas supply pipe extending from a source of an additional gas is connected to the second branch pipe. The additional gas supply pipe includes a flow rate controller for controlling the flow rate of the additional gas. In the technology of Patent Document 1, after the processing gas is supplied to the first branch pipe and the second branch pipe, the additional gas set to have a first-out flow rate larger than a predetermined flow rate (hereinafter, referred to as a “processing flow rate”) is supplied to the additional gas supply pipe. Accordingly, the pressure of the additional gas supply pipe is rapidly increased. Then, the flow rate of the additional gas is returned to the processing flow rate. Then, a high frequency power is supplied to the upper electrode to generate plasma. Accordingly, in the technology of Patent Document 1, a time required until the flow rate of the additional gas supplied into the processing container reaches the processing flow rate is shortened.